When the Night Has Come and the Land is Dark, the Moon is the Only Light We’ll See: Shrimp Farming 101

“When the Night Has Come and the Land is Dark, the Moon is the Only Light We’ll See: Shrimp Farming 101”

By Liam Hassett

People have been farming shrimp in the Delta as a way of life for generations. However, the manner in which it has been traditionally practiced has dominantly changed, but not lost. Huge demands for shrimp worldwide have made shrimp farming, in areas of the world where the climate can support it, a lucrative business. Rice and shrimp farming definitely dominate the commercial productions industries of agriculture and aquaculture in the Mekong Delta. To make room for all this, tens of thousand of hectares of mangrove and melaleuca forests have been deforested. Driving down the road in the delta there is rice paddy after rice paddy for as far as the eye can see. Then, in the blink of an eye you cross over from rice paddies to shrimp ponds stretching into the distance. This style of intensive farming puts Vietnam on the map as one of the leading producers in the world.

Vietnam follows the lunar calendar; hence here Tet or lunar New Year is THE holiday to celebrate. Most people in the US are at least mildly familiar with the Farmers’ Almanac that also follows the lunar calendar. Farmers in Vietnam, specifically traditional shrimp farmers schedule their harvests on 2-week cycles following the full moon and the new moon. It is when the shrimp are on the move. To adapt to this some interesting practices in intensive systems have adjusted to this. Intensive shrimp farmers cut off the eyes of the shrimp, blinding them, to limit their senses on the true full moon. This allows for bulk harvests, able to be sold directly to processors, on a twice a year rotation. Twice a year ponds are drained and restocked with all sorts of feed, oxygen, biofloc or other inputs in between. It can be highly energy intensive when everything is added up.

Integrated farming has two schools of thought, extensive and rotation. Rotation follows more intensive practices, but adapts to the changes in water salinity between the dry and rainy seasons. Near the coast farmers grow rice (with some tilapia for personal consumption) in the rainy season when water salinity is low, then switch to shrimp when brackish waters inundate during the dry season. Extensive aquaculture, more common near the coast, relies more so on processes found in nature than that of mimicking it. In the extensive style of shrimp farming, shrimp farmers keep natural vegetation, like mangroves to supply habitat and organic matter for shrimp in and around their ponds. This helps to supply food and regulate water temperatures and provide a healthier environment for the shrimp and other life in the ponds. Twice a month under the light of the full moon, when tides are highest, farmers open the gates of their ponds to catch mature shrimp migrating out in the canals attempting to make it to the sea. The tonnage is less per harvest, not enough to sell directly to processors, but allows for a more frequent and consistent source of income.

The class visited research sites that examined both styles. In some cases we roared through the delta on jet boats to reach the farms. We sat with, spoke to and ate with the farmers who used traditional methods. They fed us fish and shrimp caught in their ponds. Not for nothing the taste was out of this world compared to even the fresh stuff from the supermarket or restaurant. Happy cows make good cheese, and happy seafood is delicious.

For anyone that can grasp the basics of economics, you get more bang for your đồng when you can cut out as many middlemen as possible between the farm and the table. There are pros and cons to both intensive and extensive styles of shrimp farming. With such high worldwide demand for shrimp, bulk tonnage makes sense for bulk harvests. It comes down to simple dollars and cents when you can harvest in bulk and sell directly to a processor, but something more than just taste is lost. After all the externalities are factored in, like the loss of mangroves (that provide a wealth of ecoservices) and the energy-intensive intensive shrimp farms the question to ask is, what is the true cost of shrimp farming in the long run to people in the delta?